Ma Yao-Feng, Sung Ming-Je, Huang Ding-Wei
Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
Appl Opt. 2010 Dec 20;49(36):6979-85. doi: 10.1364/AO.49.006979.
The polarization dependence of directional couplers (DC) formed by silicon-on-insulator (SOI) slot waveguides was studied, and its applications as highly efficient polarization beam splitters (PBSs) and polarization-independent directional couplers (PIDCs) were investigated. The coupling lengths for the quasi-TE and quasi-TM modes may vary with the waveguide geometry due to structural birefringence; thus numerical simulations of the coupling effects in the directional couplers with different aspect ratios and waveguide spacing were conducted to obtain the optimal design parameters for high efficiency as well as compact device size. The lengths of the coupling regions of the designed PBS and PIDC are 47.61 and 23.13 μm, respectively, and they delivered good performance, with an extinction ratio greater than 20 and 1 dB bandwidth larger than 100 nm. The tolerance of fabrication error in the practical device is also discussed.
研究了由绝缘体上硅（SOI）槽波导形成的定向耦合器（DC）的偏振依赖性，并研究了其作为高效偏振光束分离器（PBS）和偏振无关定向耦合器（PIDC）的应用。由于结构双折射，准TE和准TM模式的耦合长度可能会随波导几何形状而变化；因此，对具有不同纵横比和波导间距的定向耦合器中的耦合效应进行了数值模拟，以获得高效率以及紧凑器件尺寸的最佳设计参数。所设计的PBS和PIDC的耦合区域长度分别为47.61和23.13μm，它们具有良好的性能，消光比大于20，1dB带宽大于100nm。还讨论了实际器件中制造误差的容限。
